Detachable bit



I. J. BERSCHEID DETAGHABLE BIT Filed June 1944 VENTU BERSBHEJD ATTD R N Patented Feb. 1, 1949 @uNITED 1 STAT ES PATENT OFFICE 7 DETACHABLE BIT Irvine J. Berscheid, Bissett, Manitoba, Canada Application June 9, 1944, Serial No. 539,425

9 Claims. (01. 25564) drill shank having a self-fitting bit removably securable therewith by the tamping action of the shank member, thus enabling the bit to be removed from the drill hole at'the same time as, and together with the shank.

-It is also an object of the invention to provide a drilling unit which may be made in suitable material of any practical size and is insertable into standard types of power drilling equipment.

A further object of the invention is to furnish a drilling bit which is inexpensive to produce, will operate efiiciently and which will permit of readyreplacement when the cutting edges of the bit member become dulled and useless for rapid drilling, thus saving time and reducing the cost of;many types of drilling operations.

Referring to the drawings,- the bit member com prises the cutting edges Ii] having the depressions I I therebetween and the end I2 on which are disposed the integral and upwardly projecting finger members l3, I4, I5 and I6, each having a chamfered surface 2| at the upper extremity thereof. Between the end I2 and the lower part ll of the depressions, is a conical surface I8 preferably having the tapered channels I9 disposed around the periphery thereof and in the centre of the bit is an aperture 20 adapted to feed coolant to the cutting edges I0. It will be seen that the inner vertical surfaces 22 of the finger members are joined to the end I2 by an inclined surface 23,

thus forming a large area of contact between the fingers and the end I2 of the bit;

The shank member '24 comprises a base 25 having recesses 26, 21, 28 and 29 disposed therein to correspond with the finger members I 3, I4, I5 and I6 of the bit. The recesses are formed by the sides 30 which are joined by a flange 3I having an undercut portion 32, while the base 34 of each recess consists of a surface sloped at an angle to the axis of the shank substantially different from 25 the angle between the surfaces 23 of the bit and the vertical axis thereof. Longitudinally through the shank is an aperture 33 adapted to feed cool- -In general the invention comprises a drilling member having a detachable cutting bit at the extremity thereof, which bit member includes rearwardly projecting finger members and is adapted to seat and lock itself upon percussive contact with a cooperating shank, being removable therefrom when the cutting surfaces of the bit have become dull and worn.

In the drawings Figure 1 is a perspective view of the detachable bit member.

Figure 2 is a plan view looking upwardly of the detachable bit member.

Figure dis a perspective view of the shank portion of the drill.

Figure 4 is a plan view looking upwardly of the shank portion of the drill.

Figure 5 is a vertical sectional view of the shank on the line 5-5 in Figure 4.

I Figure 6-is a vertical sectional view of the bit taken on-the lines 6-45 in Figure 2.

Figure 7 is a vertical sectional view of the shank and bit in assembled position.

Figureytl is a vertical sectional view of the shank ab iia 1 5a, .7

ant therethrough and disposed in alignment with the aperture of the bit.

- In operating position, the base 25 of the shank is placed parallel to the end. I2 of the bit, the fingers of the bit being inserted into the corresponding recesses of the shank, as best seen in Figure 7. The bit is then pushed home until the inner and upper portions 36 of the fingers are contiguous with the inclined bases 34 of the recesses in the shank. In this position it will be seen clearly from Figure '7 that the chamfered surfaces 2| make an angle with the bases 34 of the recesses.

The body 35 of the shank being now inserted into a power drill, the drill bit is then fed against the material to be drilled. As best seen in Figure 8, the bases 34 of the shank now exert heavy pressure on the fingers I 3, I4, I5 and I 6, the force being first exerted on the upper and inner portions 36 of the fingers and then gradually extending down through the chamfered edges 2|, progressively deforming them until by the powerful tamping action of the shank, the material of the upper portions of the fingers is forced inwardly thus locking the deformed material against the undercut portions of the flanges.

It will be understood by reference to Figures j '7 and 8 that when this tamping or riveting action has proceeded to such apoint that the undercut spaces 32 are more or less completely filled up by the deformed material of the fingers, the surfaces I2 and 25 will then be adjacent to each other, as in Figure 8, and in this position it will also be seen that the sloping flange surfaces 3| are finally in close contact with the inwardly disposed surfaces 23 of the projecting fingers, thus further increasing the locking action between the bit and shank.

It is evident that when, through the bluntness of the cutting edges or for any other reason, it is advisable to remove the bit from the shank,

the conical surfaces 98 provide a ready means of gripping the bit so as to enable it to be pulled out of engagement with the shank. Thus it will be seen that the structure described adequately fulfills the objects of the invention.- Although in this invention preferred embodiments of the Various components have been described andillustrated herein, it is to be understood that I do not wish to limit the invention to such specific disclosure and it will be seen, for example, that although. a bit member having four rearwardly projecting finger members is represented and referred to, a bit .member having only two or more than four similar fingers is included within thescope and nature of the invention as de- -fined by the claims appended.

upon percussive contact between said bit and shank, to retain said bit from axial dislodgment during operation, said fingers forming torsion applying means between said bit and shank.

2. In drills, the combination of a detachable bit and a shank member, the bit member ineluding forwardly located cutting surfaces and rearwardly located integral projecting finger members having chamfered ends, the said shank including recesses having means therein cooperatively to receive the finger members, means in connection with the said shank for retaining said bit inlocking engagement with said shank, each of said recesses having a sloping wall designedto form an acuteangle with the chamfered end of a received finger-member to-deform thesaid chamfered end of the said received finger member into said locking engagement with said shank upon percussive contact between said bit and said shank, to retain said bit from axial dislodgment during operation, said fingers'forming torsion applying means between said bit and said shank.

3. In drills, the combination of a detachable bit member and a shank member, the said bit member including cutting surfaces and rearwardly projecting finger members, each of said finger members terminating in a knife edge, said shank including recesses to receive the said finger members, each of said recesses including a defining wall engageable with the knife edge of a received finger member to deform the knife edge of said received finger member into locking en gagementwith said shank upon tamping of said shank against said..bit,'and means in-connection with the defining wall of each of said recesses for receiving the deformed knife edge of said received finger member in the said locking engagement, to retain said bit from axial dislodgment during operation, said fingers forming torsion applying means between said bit and said shank.

4. In drills, the combination of a detachable bit member and a shank member, said bit member including cutting surfaces and rearwardly projecting finger members, each of said finger members having a knife edge at the upper portion thereof, and said shank member having recesses therein'to receive the said finger members, each of said recesses including a wall having an undercutportion therein, the said knife edge and the upper portion being adapted to be deformed by the said wall into locking engagement with said undercut portion of the said wall upon percussive contact between the said shank and bit, to retain said bitfrom axial dislodgment during operation,

said finger members forming torsion applyingmeans between said bit and shank.

5. In drills the combination of a detachable bit member and a shank member as claimed in claim 1, in which each of the said recesses has: an'endwall inclined at a predetermined angle to the vertical axis of the said shank to engage the side of a received finger member, and side walls, one of which has an undercut portion into which portion the end of the said received finger member is securable by tamping.

6. In drills, the combination'of a detachable bit memberand a shank member as claimed in claim 1, in which each of the said finger members hasa charnfered end and each of the said recesses has an inclined base wall, each chamfered end having a surface thereon inclined to the vertical axis of the bit at an angle substantially different from the angle between the said inclined base wall and the vertical axis of the said shank.-

7. In drills, the combination of a detachable bit member, and a shank member as claimed'in claim 2, in which a projecting flange is located within each of the said recesses to form an undercut portion into which the end of a received finger member is adapted-to be removably secured by tamping betweensaid shank and bit:

8. In' drills, the combination of a detachable bit member with a shank member, the said bit member including forwardly located'cutting edges having'depressions'therebetween, and a rear surface having integral finger members projecting upwardly therefrom, a plurality of tapered channels located on the edge of'the said bit, the up-' ward end of each of the tapered'channels terminating'adjacent to one of the said finger members and the downward end of each of said ta pered channels terminating adjacent to one of thesaid depressions between 'thesaid cutting edges, and the said shank having recesses therein cooperative-1y engageable with said finger mem" bers and adapted to be alignedand-detachably ceiving the said finger members therein, each of the said recesses including a defining wall having an undercut portion and being cooperatively er'igageable with the said deformable portion of REFERENCES CITED one of the said finger members for locking 8. re- ,ceived fing member withsaid undercut portion The following references are of record in the of said defining wall upon percussive contact of me of thls Patent:

said shank with said bit, to retain said bit from 5 UNITED STATES PATENTS axiai dislodgment during operation, said fingers Number Name 1 Date 7 gg fig lg applying between Sam mt 1,738,883 Garino Dec, 10, 1929 2,051,306 Liddicoat Aug. 18, 1936 IRVINE J. BERSCHE'ID. 

